
例7 用描述法表示拋物線y=x2+1上的點(diǎn)構(gòu)成的集合.【答案】見解析 【解析】 拋物線y=x2+1上的點(diǎn)構(gòu)成的集合可表示為:{(x,y)|y=x2+1}.變式1.[變條件,變設(shè)問]本題中點(diǎn)的集合若改為“{x|y=x2+1}”,則集合中的元素是什么?【答案】見解析 【解析】集合{x|y=x2+1}的代表元素是x,且x∈R,所以{x|y=x2+1}中的元素是全體實(shí)數(shù).變式2.[變條件,變設(shè)問]本題中點(diǎn)的集合若改為“{y|y=x2+1}”,則集合中的元素是什么?【答案】見解析 【解析】集合{ y| y=x2+1}的代表元素是y,滿足條件y=x2+1的y的取值范圍是y≥1,所以{ y| y=x2+1}={ y| y≥1},所以集合中的元素是大于等于1的全體實(shí)數(shù).解題技巧(認(rèn)識集合含義的2個步驟)一看代表元素,是數(shù)集還是點(diǎn)集,二看元素滿足什么條件即有什么公共特性。

學(xué)生在初中學(xué)習(xí)了 ~ ,但是現(xiàn)實(shí)生活中隨處可見超出 ~ 范圍的角.例如體操中有“前空翻轉(zhuǎn)體 ”,且主動輪和被動輪的旋轉(zhuǎn)方向不一致.因此為了準(zhǔn)確描述這些現(xiàn)象,本節(jié)課主要就旋轉(zhuǎn)度數(shù)和旋轉(zhuǎn)方向?qū)堑母拍钸M(jìn)行推廣.課程目標(biāo)1.了解任意角的概念.2.理解象限角的概念及終邊相同的角的含義.3.掌握判斷象限角及表示終邊相同的角的方法.?dāng)?shù)學(xué)學(xué)科素養(yǎng)1.數(shù)學(xué)抽象:理解任意角的概念,能區(qū)分各類角;2.邏輯推理:求區(qū)域角;3.數(shù)學(xué)運(yùn)算:會判斷象限角及終邊相同的角.重點(diǎn):理解象限角的概念及終邊相同的角的含義;難點(diǎn):掌握判斷象限角及表示終邊相同的角的方法.教學(xué)方法:以學(xué)生為主體,采用誘思探究式教學(xué),精講多練。教學(xué)工具:多媒體。一、 情景導(dǎo)入初中對角的定義是:射線OA繞端點(diǎn)O按逆時針方向旋轉(zhuǎn)一周回到起始位置,在這個過程中可以得到 ~ 范圍內(nèi)的角.但是現(xiàn)實(shí)生活中隨處可見超出 ~ 范圍的角.例如體操中有“前空翻轉(zhuǎn)體 ”,且主動輪和被動輪的旋轉(zhuǎn)方向不一致.

《奇偶性》內(nèi)容選自人教版A版第一冊第三章第三節(jié)第二課時;函數(shù)奇偶性是研究函數(shù)的一個重要策略,因此奇偶性成為函數(shù)的重要性質(zhì)之一,它的研究也為今后指對函數(shù)、冪函數(shù)、三角函數(shù)的性質(zhì)等后續(xù)內(nèi)容的深入起著鋪墊的作用.課程目標(biāo)1、理解函數(shù)的奇偶性及其幾何意義;2、學(xué)會運(yùn)用函數(shù)圖象理解和研究函數(shù)的性質(zhì);3、學(xué)會判斷函數(shù)的奇偶性.?dāng)?shù)學(xué)學(xué)科素養(yǎng)1.數(shù)學(xué)抽象:用數(shù)學(xué)語言表示函數(shù)奇偶性;2.邏輯推理:證明函數(shù)奇偶性;3.數(shù)學(xué)運(yùn)算:運(yùn)用函數(shù)奇偶性求參數(shù);4.數(shù)據(jù)分析:利用圖像求奇偶函數(shù);5.數(shù)學(xué)建模:在具體問題情境中,運(yùn)用數(shù)形結(jié)合思想,利用奇偶性解決實(shí)際問題。重點(diǎn):函數(shù)奇偶性概念的形成和函數(shù)奇偶性的判斷;難點(diǎn):函數(shù)奇偶性概念的探究與理解.教學(xué)方法:以學(xué)生為主體,采用誘思探究式教學(xué),精講多練。

本節(jié)主要內(nèi)容是三角函數(shù)的誘導(dǎo)公式中的公式二至公式六,其推導(dǎo)過程中涉及到對稱變換,充分體現(xiàn)對稱變換思想在數(shù)學(xué)中的應(yīng)用,在練習(xí)中加以應(yīng)用,讓學(xué)生進(jìn)一步體會 的任意性;綜合六組誘導(dǎo)公式總結(jié)出記憶誘導(dǎo)公式的口訣:“奇變偶不變,符號看象限”,了解從特殊到一般的數(shù)學(xué)思想的探究過程,培養(yǎng)學(xué)生用聯(lián)系、變化的辯證唯物主義觀點(diǎn)去分析問題的能力。誘導(dǎo)公式在三角函數(shù)化簡、求值中具有非常重要的工具作用,要求學(xué)生能熟練的掌握和應(yīng)用。課程目標(biāo)1.借助單位圓,推導(dǎo)出正弦、余弦第二、三、四、五、六組的誘導(dǎo)公式,能正確運(yùn)用誘導(dǎo)公式將任意角的三角函數(shù)化為銳角的三角函數(shù),并解決有關(guān)三角函數(shù)求值、化簡和恒等式證明問題2.通過公式的應(yīng)用,了解未知到已知、復(fù)雜到簡單的轉(zhuǎn)化過程,培養(yǎng)學(xué)生的化歸思想,以及信息加工能力、運(yùn)算推理能力、分析問題和解決問題的能力。

本板塊的活動主題是“談?wù)摴?jié)日活動”(Talk about festival activities),主要是從貼近學(xué)生日常生活的角度來切入“節(jié)日”主題。學(xué)生會聽到發(fā)生在三個國家不同節(jié)日場景下的簡短對話,對話中的人們正在參與或?qū)⒁H歷不同的慶?;顒?。隨著全球化的進(jìn)程加速,國際交流日益頻繁,無論是國人走出國門還是外國友人訪問中國,都已成為司空見慣的事情。因此,該板塊所選取的三個典型節(jié)日場景都是屬于跨文化交際語境,不僅每組對話中的人物來自不同的文化背景,對話者的身份和關(guān)系也不盡相同。1. Master the new words related to holiday: the lantern, Carnival, costume, dress(sb)up, march, congratulation, congratulate, riddle, ceremony, samba, make - up, after all. 2. To understand the origin of major world festivals and the activities held to celebrate them and the significance of these activities;3. Improve listening comprehension and oral expression of the topic by listening and talking about traditional festivals around the world;4. Improve my understanding of the topic by watching pictures and videos about different traditional festivals around the world;5. Review the common assimilation phenomenon in English phonetics, can distinguish the assimilated phonemes in the natural language flow, and consciously use the assimilation skill in oral expression. Importance:1. Guide students to pay attention to the attitude of the speaker in the process of listening, and identify the relationship between the characters;2. Inspire students to use topic words to describe the festival activities based on their background knowledge. Difficulties:In the process of listening to the correct understanding of the speaker's attitude, accurately identify the relationship between the characters.

*wide range of origins(= a great number of different origins, many kinds of origins)*It featured a parade and a great feast with music, dancing, and sports. (=A parade and a great feast with music, dancing, and sports were included as important parts of the Egyptian harvest festival.)*.. some traditions may fade away and others may be established.(= Some traditions may disappear gradually, while other new traditions may come into being.)Step 6 Practice(1) Listen and follow the tape.The teacher may remind the students to pay attention to the meaning and usage of the black words in the context, so as to prepare for the completion of the blanks in activity 5 and vocabulary exercises in the exercise book.(2) Students complete the text of activity 5 by themselves.The teacher needs to remind the students to fill in the blanks with the correct form of the vocabulary they have learned in the text.Students exchange their answers with their partners, and then teachers and students check their answers.(3)Finish the Ex in Activity 5 of students’ book.Step 7 Homework1. Read the text again, in-depth understanding of the text;2. Discuss the origin of festivals, the historical changes of related customs, the influence of commercial society on festivals and the connotation and essential meaning of festivals.3. Complete relevant exercises in the guide plan.1、通過本節(jié)內(nèi)容學(xué)習(xí),學(xué)生是否理解和掌握閱讀文本中的新詞匯的意義與用法;2、通過本節(jié)內(nèi)容學(xué)習(xí),學(xué)生能否結(jié)合文本特點(diǎn)快速而準(zhǔn)確地找到主題句;3、通過本節(jié)內(nèi)容學(xué)習(xí),學(xué)生能否理清論說文的語篇結(jié)構(gòu)和文本邏輯,了解節(jié)日風(fēng)俗發(fā)展與變遷,感悟節(jié)日的內(nèi)涵與意義。

The price is the same as(the price was)before the war.價格與戰(zhàn)前相同。(4)定語從句中的“關(guān)系代詞+助動詞be”可以省略。The ticket(that/which was)booked by his sister has been sent to him.他妹妹訂的那張票已送到了他那里。Step 5 PracticeActivity 3(1) Guide students to complete the four activities in the Using Structures part of exercise book, in which activities 1 and 2 focus on ellipsis in dialogue answers, activity 3 focus on signs and headlines, two typical situations where ellipsis is used, and activity 4 focus on ellipsis in diary, an informal style.(2) Combine the examples in the above activities, ask students to summarize the omitted situations in groups, and make their own summary into a poster, and post it on the class wall after class to share with the class.(This step should give full play to the subjectivity of students, and teachers should encourage students to conclude different ellipsis phenomena according to their own understanding, they can conclude according to the different parts omitted in the sentence.)Step 6 Homework1. Understand and master the usages of ellipsis;2. Finish the other exercises in Using structures of Workbook.1、通過本節(jié)內(nèi)容學(xué)習(xí),學(xué)生是否理解和掌握省略的用法;2、通過本節(jié)內(nèi)容學(xué)習(xí),學(xué)生能否根據(jù)上下文語境或情景恢復(fù)句子中省略的成分,體會使用省略的效果;3、通過本節(jié)內(nèi)容學(xué)習(xí),學(xué)生能否獨(dú)立完成練習(xí)冊和導(dǎo)學(xué)案中的相關(guān)練習(xí)。

該板塊的活動主題是“介紹一個有顯著文化特征的地方”( Describe a place with distinctive cultural identity)。該板塊通過介紹中國城繼續(xù)聚焦中國文化。本單元主題圖呈現(xiàn)的是舊金山中國城的典型景象, Reading and Thinking部分也提到中國城,為該板塊作鋪墊。介紹中國城的目的主要是體現(xiàn)中國文化與美國多元文化的關(guān)系,它是美國多元文化的重要組成部分。中國城也是海外華人的精神家園和傳播中國文化的重要窗口,外國人在中國城能近距離體驗(yàn)中國文化。1. Read the text to understand the cultural characteristics of Chinatown in San Francisco and the relationship between Chinese culture and American multiculturalism;2. Through reading, learn to comb the main information of the article, understand the author's writing purpose and writing characteristics;3. Learn to give a comprehensive, accurate, and organized description of the city or town you live in;Learn to revise and evaluate your writing.Importance:1. Guide the students to read the introduction of Chinatown in San Francisco and grasp its writing characteristics;2. Guide students to introduce their city or town in a comprehensive, accurate and organized way;3. Learn to comb the main information of the article, understand the author's writing purpose, and master the core vocabulary.

Activity 81.Grasp the main idea of the listening.Listen to the tape and answer the following questions:Who are the two speakers in the listening? What is their relationship?What is the main idea of the first part of the listening? How about the second part?2.Complete the passage.Ask the students to quickly review the summaries of the two listening materials in activity 2. Then play the recording for the second time.Ask them to complete the passage and fill in the blanks.3.Play the recording again and ask the students to use the structure diagram to comb the information structure in the listening.(While listening, take notes. Capture key information quickly and accurately.)Step 8 Talking Activity 91.Focus on the listening text.Listen to the students and listen to the tape. Let them understand the attitudes of Wu Yue and Justin in the conversation.How does Wu Yue feel about Chinese minority cultures?What does Justin think of the Miao and Dong cultures?How do you know that?2.learn functional items that express concerns.Ask students to focus on the expressions listed in activity. 3.And try to analyze the meaning they convey, including praise (Super!).Agree (Exactly!)"(You're kidding.!)Tell me more about it. Tell me more about it.For example, "Yeah Sure." "Definitely!" "Certainly!" "No kidding!" "No wonder!" and so on.4.Ask the students to have conversations in small groups, acting as Jsim and his friends.Justin shares his travels in Guizhou with friends and his thoughts;Justin's friends should give appropriate feedback, express their interest in relevant information, and ask for information when necessary.In order to enrich the dialogue, teachers can expand and supplement the introduction of Miao, dong, Lusheng and Dong Dage.After the group practice, the teacher can choose several groups of students to show, and let the rest of the students listen carefully, after listening to the best performance of the group, and give at least two reasons.

二、說教學(xué)目標(biāo)1.認(rèn)識“渡、蔭”等9個生字,會寫“傘、姨”等8個生字。 2.默讀課文,根據(jù)情境展開合理想象,并把想象的內(nèi)容寫下來。? 3.正確流利地朗讀課文,有感情地朗讀重點(diǎn)句子,感受作者對喜鵲的喜愛之情。三、說教學(xué)重難點(diǎn)1.識記生字,朗讀課文,根據(jù)情境展開合理想象,并把想象的內(nèi)容寫下來。(重點(diǎn)) 2.感受“我”對楓樹和喜鵲的喜愛,感受故事的童趣。(難點(diǎn))四、說教法和學(xué)法1.創(chuàng)設(shè)情境法主要是通過創(chuàng)設(shè)情境,讓學(xué)生進(jìn)入情境中,激發(fā)學(xué)生的內(nèi)在情感,為學(xué)生進(jìn)行想象找到共鳴點(diǎn)和切入點(diǎn)。? 2.閱讀法我采用朗讀、默讀。教師范讀,表演讀,分角色讀等引導(dǎo)學(xué)生感受作者對喜鵲的喜愛之情。3.練習(xí)設(shè)計(jì)法《語文課程標(biāo)準(zhǔn)》中指出'語文課程是一門學(xué)習(xí)語言文字運(yùn)用的綜合性、實(shí)踐性課程',充分說明了語文練習(xí)的重要性。練習(xí)有助于學(xué)生形成熟練的技能和發(fā)展學(xué)生的思維能力。因此,設(shè)計(jì)語言訓(xùn)練的練習(xí),是在培養(yǎng)學(xué)生的應(yīng)用意識、實(shí)踐能力。新課程標(biāo)準(zhǔn)倡導(dǎo)'自主、合作、探究'的學(xué)習(xí)方式,于是我將'學(xué)習(xí)的主動權(quán)還給學(xué)生'。通過自主朗讀、小組合作交流、討論探究等方式開展。

四、說教學(xué)過程(一)結(jié)合現(xiàn)實(shí)、自然導(dǎo)入隨著我國開放的深入發(fā)展,國外的科學(xué)、文化、技術(shù)以及資產(chǎn)階級的腐朽思想,生活作風(fēng)等等也隨之大量涌來,我們應(yīng)采取怎樣的態(tài)度和方法才是正確的呢?魯迅先生在30年代就繼承文化遺產(chǎn)問題曾寫過一篇雜文,我們可以從中獲得那些啟示呢?(二)整體感知、疏瀹文意1.請同學(xué)介紹“我所知道的魯迅”,教師補(bǔ)充寫作背景。教師有針對性的進(jìn)行預(yù)習(xí)檢查,能促使學(xué)生養(yǎng)成課前預(yù)習(xí)的習(xí)慣。2.理清文章的思路,分析文章的整體結(jié)構(gòu)教師范讀課文,針對較難的字音進(jìn)行正讀。學(xué)生快速瀏覽課文,把握全文框架,小組討論后分出層次。(讓學(xué)生通過自主合作探究來概括文意可以讓同學(xué)們參與到教學(xué)活動中,鍛煉學(xué)生實(shí)際動手能力)

本環(huán)節(jié)利用多媒體展示的教學(xué)手段,通過創(chuàng)設(shè)優(yōu)美的情景來渲染氣氛,引導(dǎo)學(xué)生接受美的熏陶,增強(qiáng)學(xué)生學(xué)習(xí)興趣。教師先播放蓮花的圖片,讓學(xué)生們談?wù)勛约郝?lián)想到的詩詞曲賦或文章,來激發(fā)學(xué)生的學(xué)習(xí)熱情,隨后教師總結(jié),引出現(xiàn)代寫荷花的名篇《荷塘月色》,從而導(dǎo)入新課。導(dǎo)語部分的設(shè)計(jì)既給了學(xué)生美感享受又自然的導(dǎo)入了新課。(二)初讀文本,把握結(jié)構(gòu)本環(huán)節(jié)主要采用了小組合作法讓學(xué)生以小組合作的形式探索文章夜游順序和情感變化這兩條線索發(fā)展,教師適當(dāng)?shù)倪M(jìn)行點(diǎn)撥,讓學(xué)生通過探索文章線索完成對本課“圓形結(jié)構(gòu)”把握。目的是發(fā)揮學(xué)生主導(dǎo)作用,自主學(xué)習(xí)、把握文章結(jié)構(gòu)美。(三)選讀文本,分析手法在本環(huán)節(jié)中主要運(yùn)用講授法和問答法。讓學(xué)生反復(fù)誦讀課文第4、5、6段,找出作者使用修辭手法修飾了的景物,隨后師生問答作者運(yùn)用了什么修辭手法來描寫“荷塘”“月色”“荷花”“荷香”等景物的,又達(dá)到了什么樣的效果呢?最后由教師來具體講解本文中學(xué)生不熟悉的寫作手法(如:通感)。

此環(huán)節(jié)運(yùn)用的是合作探究法,采用小組討論的形式開放回答即可。通過本課的學(xué)習(xí),學(xué)生可以總結(jié)歸納出辛棄疾主張抗敵,收復(fù)失地的愛國熱情對南宋政府茍且偏安的不滿,吸取的歷史教訓(xùn),告誡當(dāng)使用者不要草率用兵。對于決策者提出警告,抒發(fā)自己壯志難酬的感慨,教師總結(jié)歸納即可。本詩寫出最大特點(diǎn)就是大量典故的運(yùn)用。學(xué)生可以本詩對用點(diǎn)表達(dá)自己的看法,我將在在PPT展示詩歌用典的意義,意在幫助學(xué)生理解更好用典這種詩歌技巧。本篇是一首詠史懷古詩,本單元學(xué)習(xí)了兩首同題材詩歌,有必要使學(xué)生掌握一類型的詩歌鑒賞方法。(五)比較閱讀 品味歷史這一環(huán)節(jié)PPT將展示上次課程學(xué)習(xí)的《念奴嬌赤壁懷古》并從內(nèi)容,形式等角度分析異同,采用提問的方法。此環(huán)節(jié)結(jié)束后簡要?dú)w納詠史懷古詩類型。目的是鞏固加強(qiáng)對于詠史懷古題材詩歌理解,理解歸納詠史懷古詩題材類型。(六)布置作業(yè) 鞏固感知鑒賞李白《越中覽古》我將采用習(xí)題的形式,目的是使學(xué)生在實(shí)踐中運(yùn)用所學(xué)方法鑒賞詠史懷古詩。

讀,是學(xué)生接觸作品最直接的方式。初讀詞作,讓學(xué)生聽示范讀,并且在課本注解的提示下,解決詞作的讀音問題。再進(jìn)一步了解詞人情況、本詞的創(chuàng)作背景以及懷古詠史詩詞的基本情況。通過齊讀的方式,親身感受詞作的音韻之美。讀,是放飛想象的最好方式。再讀詞作,通過誦讀上闕內(nèi)容,想象上闕描繪了一幅什么樣的情景?用了哪些富有表現(xiàn)力的詞來極力描繪這些景象?呈現(xiàn)出何種意境?有何作用?并且利用智慧課堂進(jìn)行填空和選擇。讀,是把握內(nèi)容的最有用的方式。通過智慧課堂隨機(jī)選擇,引導(dǎo)學(xué)生分角色誦讀下闕,分析三國時的周瑜與此時的詞人蘇軾的形象。在對比中,感受周瑜的情場、官場、戰(zhàn)場,場場得意的情況,和蘇軾的黃州、惠州、儋州,州州失意的人生境遇。理解周瑜之于蘇軾而言,是某種程度上熱切向往的和難以企及的夢。讀,也是賞析體悟作品主要方式。學(xué)生再次齊讀下闕,賞析詞作最后兩句“人生如夢,一尊還酹江月”表達(dá)了作者怎樣的情感?來完成本篇內(nèi)容的學(xué)習(xí)。

二、典例解析例3.某公司購置了一臺價值為220萬元的設(shè)備,隨著設(shè)備在使用過程中老化,其價值會逐年減少.經(jīng)驗(yàn)表明,每經(jīng)過一年其價值會減少d(d為正常數(shù))萬元.已知這臺設(shè)備的使用年限為10年,超過10年 ,它的價值將低于購進(jìn)價值的5%,設(shè)備將報廢.請確定d的范圍.分析:該設(shè)備使用n年后的價值構(gòu)成數(shù)列{an},由題意可知,an=an-1-d (n≥2). 即:an-an-1=-d.所以{an}為公差為-d的等差數(shù)列.10年之內(nèi)(含10年),該設(shè)備的價值不小于(220×5%=)11萬元;10年后,該設(shè)備的價值需小于11萬元.利用{an}的通項(xiàng)公式列不等式求解.解:設(shè)使用n年后,這臺設(shè)備的價值為an萬元,則可得數(shù)列{an}.由已知條件,得an=an-1-d(n≥2).所以數(shù)列{an}是一個公差為-d的等差數(shù)列.因?yàn)閍1=220-d,所以an=220-d+(n-1)(-d)=220-nd. 由題意,得a10≥11,a11<11. 即:{█("220-10d≥11" @"220-11d<11" )┤解得19<d≤20.9所以,d的求值范圍為19<d≤20.9

二、典例解析例4. 用 10 000元購買某個理財(cái)產(chǎn)品一年.(1)若以月利率0.400%的復(fù)利計(jì)息,12個月能獲得多少利息(精確到1元)?(2)若以季度復(fù)利計(jì)息,存4個季度,則當(dāng)每季度利率為多少時,按季結(jié)算的利息不少于按月結(jié)算的利息(精確到10^(-5))?分析:復(fù)利是指把前一期的利息與本金之和算作本金,再計(jì)算下一期的利息.所以若原始本金為a元,每期的利率為r ,則從第一期開始,各期的本利和a , a(1+r),a(1+r)^2…構(gòu)成等比數(shù)列.解:(1)設(shè)這筆錢存 n 個月以后的本利和組成一個數(shù)列{a_n },則{a_n }是等比數(shù)列,首項(xiàng)a_1=10^4 (1+0.400%),公比 q=1+0.400%,所以a_12=a_1 q^11 〖=10〗^4 (1+0.400%)^12≈10 490.7.所以,12個月后的利息為10 490.7-10^4≈491(元).解:(2)設(shè)季度利率為 r ,這筆錢存 n 個季度以后的本利和組成一個數(shù)列{b_n },則{b_n }也是一個等比數(shù)列,首項(xiàng) b_1=10^4 (1+r),公比為1+r,于是 b_4=10^4 (1+r)^4.

二、典例解析例10. 如圖,正方形ABCD 的邊長為5cm ,取正方形ABCD 各邊的中點(diǎn)E,F,G,H, 作第2個正方形 EFGH,然后再取正方形EFGH各邊的中點(diǎn)I,J,K,L,作第3個正方形IJKL ,依此方法一直繼續(xù)下去. (1) 求從正方形ABCD 開始,連續(xù)10個正方形的面積之和;(2) 如果這個作圖過程可以一直繼續(xù)下去,那么所有這些正方形的面積之和將趨近于多少?分析:可以利用數(shù)列表示各正方形的面積,根據(jù)條件可知,這是一個等比數(shù)列。解:設(shè)正方形的面積為a_1,后續(xù)各正方形的面積依次為a_2, a_(3, ) 〖…,a〗_n,…,則a_1=25,由于第k+1個正方形的頂點(diǎn)分別是第k個正方形各邊的中點(diǎn),所以a_(k+1)=〖1/2 a〗_k,因此{(lán)a_n},是以25為首項(xiàng),1/2為公比的等比數(shù)列.設(shè){a_n}的前項(xiàng)和為S_n(1)S_10=(25×[1-(1/2)^10 ] )/("1 " -1/2)=50×[1-(1/2)^10 ]=25575/512所以,前10個正方形的面積之和為25575/512cm^2.(2)當(dāng)無限增大時,無限趨近于所有正方形的面積和

課前小測1.思考辨析(1)若Sn為等差數(shù)列{an}的前n項(xiàng)和,則數(shù)列Snn也是等差數(shù)列.( )(2)若a1>0,d<0,則等差數(shù)列中所有正項(xiàng)之和最大.( )(3)在等差數(shù)列中,Sn是其前n項(xiàng)和,則有S2n-1=(2n-1)an.( )[答案] (1)√ (2)√ (3)√2.在項(xiàng)數(shù)為2n+1的等差數(shù)列中,所有奇數(shù)項(xiàng)的和為165,所有偶數(shù)項(xiàng)的和為150,則n等于( )A.9 B.10 C.11 D.12B [∵S奇S偶=n+1n,∴165150=n+1n.∴n=10.故選B項(xiàng).]3.等差數(shù)列{an}中,S2=4,S4=9,則S6=________.15 [由S2,S4-S2,S6-S4成等差數(shù)列得2(S4-S2)=S2+(S6-S4)解得S6=15.]4.已知數(shù)列{an}的通項(xiàng)公式是an=2n-48,則Sn取得最小值時,n為________.23或24 [由an≤0即2n-48≤0得n≤24.∴所有負(fù)項(xiàng)的和最小,即n=23或24.]二、典例解析例8.某校新建一個報告廳,要求容納800個座位,報告廳共有20排座位,從第2排起后一排都比前一排多兩個座位. 問第1排應(yīng)安排多少個座位?分析:將第1排到第20排的座位數(shù)依次排成一列,構(gòu)成數(shù)列{an} ,設(shè)數(shù)列{an} 的前n項(xiàng)和為S_n。

本節(jié)通過學(xué)習(xí)用二分法求方程近似解的的方法,使學(xué)生體會函數(shù)與方程之間的關(guān)系,通過一些函數(shù)模型的實(shí)例,讓學(xué)生感受建立函數(shù)模型的過程和方法,體會函數(shù)在數(shù)學(xué)和其他學(xué)科中的廣泛應(yīng)用,進(jìn)一步認(rèn)識到函數(shù)是描述客觀世界變化規(guī)律的基本數(shù)學(xué)模型,能初步運(yùn)用函數(shù)思想解決一些生活中的簡單問題。課程目標(biāo)1.了解二分法的原理及其適用條件.2.掌握二分法的實(shí)施步驟.3.通過用二分法求方程的近似解,使學(xué)生體會函數(shù)零點(diǎn)與方程根之間的聯(lián)系,初步形成用函數(shù)觀點(diǎn)處理問題的意識.數(shù)學(xué)學(xué)科素養(yǎng)1.數(shù)學(xué)抽象:二分法的概念;2.邏輯推理:用二分法求函數(shù)零點(diǎn)近似值的步驟;3.數(shù)學(xué)運(yùn)算:求函數(shù)零點(diǎn)近似值;4.數(shù)學(xué)建模:通過一些函數(shù)模型的實(shí)例,讓學(xué)生感受建立函數(shù)模型的過程和方法,體會函數(shù)在數(shù)學(xué)和其他學(xué)科中的廣泛應(yīng)用.

Step 3 Analyzing article structureActivity 31. Teachers raise questions to guide students to analyze the chapter structure of this diary and think about how to describe the festival experience. (1)What should be included in the opening/body/closing paragraph(s)?(2)How did the writer arrange his/her ideas?(3)What kind of interesting details did the writer describe?(4)How did the writer describe his/her feelings/emotions during the event?2. Students read and compare the three sentence patterns in activity 2. Try to rewrite the first paragraph of the diary with these three sentence patterns. After that, students exchange corrections with their partners. Such as:●This was my first time spending three days experiencing the Naadam Festival in China’s Inner Mongolia Autonomous Region and it was an enjoyable and exciting experience. ●I'll never forget my experience at the Naadam Festival because it was my first time to watch the exciting Mongolian games of horse racing, wrestling, and archery so closely. ●I'll always remember my first experience at the Naadam Festival in China’s Inner Mongolia Autonomous Region because it was so amazing to spend three days witnessing a grand Mongolian ceremony. Step 4 Accumulation of statementsActivity 41. Ask the students to read the diary again. Look for sentences that express feelings and emotions, especially those with the -ing form and the past participle. Such as:● …h(huán)orse racing, wrestling, and archery, which are all so exciting to watch. ● some amazing performances● I was surprised to see…● I was a little worried about. . . ● feeling really tiredOther emotional statements:●I absolutely enjoyed the archery, too, but the horse races were my favourite part. ●I'm finally back home now, feeling really tired, but celebrating Naadam with my friend was totally worth it. ●He invited me back for the winter to stay in a traditional Mongolian tent and cat hot pot. I can’t wait!2. In addition to the use of the -ing form and the past participle, the teacher should guide the students in the appreciation of these statements, ask them to memorize them, and encourage them to use them reasonably in writing practice.
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